The Gunners had taken a single point from their past five away league games and were without Pierre-Emerick Aubameyang, Mesut Ozil and Aaron Ramsey for this trip to Yorkshire.
Huddersfield, which is rock bottom of the Premier League, offered little resistance but did at least score for the first time since Jan Siewert replaced David Wagner as head coach thanks to Sead Kolasinac's late own goal.
Victory moves Arsenal a point behind fourth-placed Manchester United a the congested race for UEFA Champions League qualification, with Chelsea going to Manchester City on Monday (NZDT).
Arsenal took the lead in the 16th minute. Kolasinac's deep left-wing cross found Iwobi and his volleyed finish took a decisive deflection off Terence Kongolo.
Henrikh Mkhitaryan almost marked his return from seven weeks out with a foot injury with a goal but he could not beat goalkeeper Ben Hamer at the end of a flowing Arsenal move.
But he was involved in Arsenal's second before the break, Mkhitaryan teeing up Ainsley Maitland-Niles for a driven low cross that Lacazette tapped in at the back post.
Huddersfield almost replied in the 50th minute but Adama Diakhaby's driven effort from a low Kongolo cross was saved comfortably by Bernd Leno.
Iwobi should have added his second after Mkhitaryan fed him but he fired his shot into Hamer's chest, while Leno denied Diakhaby again and Huddersfield's home debutant Karlan Grant had an effort cleared off the line at the other end.
The Huddersfield fans finally had reason to celebrate after four games without a goal as Kolasinac turned into his own net in the 93rd minute, while Leno then saved from Juninho Bacuna to protect the Gunners' victory.
The battle for UEFA Champions League qualification looks set to go to the wire, with a single point splitting United in fourth and Arsenal in sixth, although Chelsea has a game in hand.
Meanwhile, Huddersfield's survival chances are ever more desperate as a 13-point gap to make up in just 12 matches appears an increasingly impossible equation.